Population dynamics of major sucking insect pests on chilli (Capsicum annum L.)

Abstract

Studies on population dynamics of major sucking insect pests revealed that the incidence of thrips, Scirtothrips dorsalis (Hood), whitefly, Bemisia tabaci (Gennadius) and leafhopper, Amrasca bigutulla bigutulla (Ishida) along with ladybird beetle, Coccinella septemtheirpunctata observed to appear on the chilli crop soon after transplanting. Incidence of thrips commenced in 19^th Standard Meteorological Week (SMW) and attained its peak on 25^th SMW (18.83 thrips /3 leaves /plant) while an infestation of whitefly was initiated in 20^th SMW then it increased gradually and reached its peak on 25^th SMW (21.20 whitefly/3 leaves /plant). The peak population of leafhoppers was recorded in 26^th SMW (10.4 leafhopper /3 leaves /plant). In case of ladybird beetle, the population ranged from 0.20 to 0.93 per plant and was on the entire crop growth period (18^th-37^th SMW). Thrips and whitefly exhibited a highly significant positive correlation with maximum temperature, a negative non-significant correlation with evening relative humidity, and a non-significant correlation with wind speed, sunshine hours, and pan evaporation while a negative non-significant correlation with rainfall. Leafhopper population showed highly significant positive correlation with minimum temperature, non-significant negative correlation with maximum temperature, non-significant positive correlation with morning and evening relative humidity, sunshine hours, and rainfall while the negative non-significant correlation with wind speed and pan evaporation. Whereas, the ladybird beetle exhibited a positive non-significant correlation with maximum temperature, wind speed, sunshine hours and a negative non-significant correlation with minimum temperature, morning and evening relative humidity, pan evaporation, and rainfall.